N,N-dimethylaniline; production methods

[Douchermann]

N,N-dimethylaniline is a yellow to brown liquid with an amine type odor (think hexamine or methylamine). It is useful in a couple procedures but is almost impossible to find.

Its synthesis uses aniline as a precursor, and almost any type of methylating agent. On orgsyn, a synthesis on the same basic principal (methylation of a primary amine) uses trimethyl phosphate as a methylating agent. AFAIK, trimethyl phosphate can be produced by esterication of methanol with phosphoric acid. I found no information to prove otherwise.

A text document I recently found gave a synthesis that used paraformaldehyde and oxalic acid dihydrate (I will gladly post this doccument if anyone would like to see it).

The method that I thought might work would be aniline reacted with methyl iodide.

C6H5NH2 + 2CH3I ----> C6H5N(CH3)2 + 2HI

I first thought of methyl bromide since alkyl bromides are usually cheaper, but then I remembered that methyl bromide is a gas till 3C IIRC. Methyl Iodide however has a BP of 42C. After the reaction, the dimethylaniline could simply be distilled off. You would also get hydroiodic acid depending on the water in the solution, which could be used to make more methyl iodide. I will attempt this once I make some methyl iodide and post how it goes. Can anyone contribute their two cents to this? Or does anyone know of another synth?

[The_Duke]

N,N-dimethylaniline is a yellow to brown liquid with an amine type odor (think hexamine or methylamine).

My DMA is almost completly clear, not really yellow or brown at all, it depends on the purity. Also, DMA does not smell like hexamine or anything like that, it has distinctly aromatic smell. It smells almost exactly like naphthalene.

[Douchermann]

Well I've got no problem making methyl iodide. I've made alkyl halides before; more specifically ethyl bromide which has a close boiling point (I keep it in my lab fridge). I've thought about DMS as well, but looking at all the troubles people have during the preparation, I tried to think of a different route. I will look back into it though.

[Douchermann]

I'm going to use the iodine + methanol + aluminum foil + H2SO4 method.

 

http://www.sciencemadness.org/talk/viewthr...tid=2727&page=3

The top post shows a synthesis. Although that method was designed for ethyl iodide, methanol can be substituted with yeilds no less than 50% (which is a terrible yeild considering the price of iodine, but I'll see how it goes).

 

As for the DMS synth, what kind of yeild did you get, using what concentration sulfuric acid. Thats all I'm worried about. If you feel like posting the whole synth in a seperate thread in the chemistry section, I'm sure this board would benefit from it but I'm sure very few people will use it.

[Douchermann]

Yeah, I'd use that method but I don't have any KI or NaI. I might order some soon though. Heck, why not try both methods. I've got I2 just sitting on the shelf, so I can probably try the first method, then order some iodide salt and try that method. I'll have to order some phosphoric acid too though, as I have yet to see a concentrated OTC source of phosphoric acid.

[Boomer]

"...wear gloves (maybe two pairs)! And a respirator maybe too"

I read that as "... and a respirator, maybe two"

 

Yeah sure one for the cat as well.

 

Is it really that bad? I mean bad as in HCN, or just bad as in huffing CHCl3, or a one-liter runaway-nitration in your fridge?

 

I ordered NaI, should come next week. So yes please do post the results, even if it will be the ethyl version for me. Still going after EtNO2 you know? And later some N-methylation would be nice.

All for the cat of course...